BARQUISIMETO, Venezuela -- Relatives of inmates missing after a Venezuelan prison riot that left at least 61 dead desperately sought news Saturday of their loved ones as detainees were moved to other jails.

“I don't know if my son is alive or dead behind those big doors,” said Elvira Rodriguez, weeping and waiting for her son Joseph, who has spent two years awaiting trial for kidnapping. “I have looked for him in all the hospitals.”

Most of the dead were killed by assault weapons, and 120 others were wounded in clashes between prison gangs and security guards at the Uribana facility in northwestern Venezuela on Friday, Antonio Maria Pineda Hospital director Ruy Medina said in an updated toll.

National Guard troops earlier surrounded the Uribana prison in Lara state as inmates in bloody clothes were taken out of the building.

Behind the barriers, relatives of the prisoners — most of them women — frantically waited for news of their loved ones and many of them were in tears. Dozens more lined up waiting for death certificates.

Carmen Garcia was seeking word on her son Edilso Rodriguez who was brought back to the prison after being treated in hospital for a bullet wound.

“We just cannot find anybody who will give us an explanation,” said the woman of about 50, who was among about 200 relatives jostling for news of their loved ones' fate.

“It was like a war movie here — with tanks rolling and shooting and too much smoke,” she said.

Vice President Nicolas Maduro, freshly back in the country after visiting recovering President Hugo Chavez in Cuba, called the riot “regrettable” and “tragic,” and said an investigation had been launched.

“The entire area for inmates still has to be brought under control,” Prison Affairs Minister Iris Varela acknowledged. It is believed to hold about 2,500 prisoners.

National Guard troops moved inside the facility and emptied the jail in a bid to completely put down the uprising, law enforcement sources said. The prisoners were being taken to other facilities.

Opposition parties immediately accused the government of exercising lax control over the prison system.

“Who will they blame for this massacre this time around?” opposition leader and former presidential candidate Henrique Capriles said on Twitter, calling the government “incapable and irresponsible.”

Humberto Prado, head of the nongovernmental Venezuelan Prison Monitoring Organization, said the government “had failed to take responsibility for the events” and instead was “piling blame on the media.”

Venezuela is notorious for the poor state of its prisons, which suffer from some of the most staggeringly high levels of overcrowding in Latin America.

Originally built to house 14,000 inmates, the country's prisons now hold almost 50,000 people, often with low sanitary standards and high levels of violence.

In August 2012, at least 25 people were killed and 43 wounded during a clash between rival gangs in Yare I prison near Caracas. In June 2011, dozens died in a riot that erupted at El Rodeo prison.